published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

published_or_final_version / Chemistry / Master / Master of Philosophy

published_or_final_version / abstract / Chemistry / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / Chemistry / Doctoral / Doctor of Philosophy

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The effect of varying substituents on structure and energies of bisketenes was studied using ab initio methods. Effect of substituents on ring closing reaction of bisketenes to the corresponding cyclobutenediones was also studied using ab initio methods. One or two of the following substituents were used to study the effect of varying substituents: BH2, CH3, NH2, OH, F, AlH2, SiH3, PH2, SH, Cl. Studies were done at the Hartree-Fock (HF), Møller-Plesset (MP2), and Density Functional Theory (B3LYP) levels of theory using the 6-31G* basis set.

A thesis presented in the University of the Witwatersrand for the degree of Doctor of Philosophy / AC 2018

by Fung Wing-chuen. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 57-59). / Abstract --- p.i / Acknowledgments --- p.ii / Biography --- p.iii / Abbreviation --- p.v-vi / Chapter 1. --- Introduction / Chapter 1.1 --- Natural O-heterocycles --- p.1 / Chapter 1.2 --- Methods for the construction of O-heterocycles --- p.5 / Chapter 1.3 --- Intramolecular nitrone cycloaddition in the construction of O-heterocycles --- p.9 / Chapter 2. --- Results and discussion / Chapter 2.1 --- Introduction --- p.12 / Chapter 2.2 --- Synthesis of 68，77，84 Via INC --- p.13 / Chapter 2.3 --- Acyclic INC of nitrones --- p.16 / Chapter 2.4 --- "Studies on 7-, 8-membered rings formation" --- p.24 / Chapter 3. --- Conclusions --- p.29 / Chapter 4. --- Experimental --- p.34 / Chapter 5. --- References --- p.57 / Chapter 6. --- List of spectra --- p.60 / Chapter 7. --- Appendices --- p.72

by Yong-li Zhong. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (p. 234-246). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web.

An enone was synthesized from delta-D-gluconolactone in four steps, involving a one-pot TPAP oxidation-K2CO3-mediated intramolecular Horner-Wadsworth-Emmons (HWE) olefination as the key step. / In this thesis, a review regarding intramolecular direct aldol reaction from 1971 to 2008 is presented. The background information on pseudo-acarviosin, valiolamine and its containing compounds, gabosines and human glutathione transferase (hGST) is introduced. / Intramolecular direct aldol reaction was investigated for the construction of cyclohexanones and cycloheptanones from carbohydrates. Amine bases, amide bases and L-proline were employed to facilitate cyclization of 1,5- and 1,6-diketones successfully. These 1,5- and 1,6-diketones were prepared from carbohydrates by standard transformations. Different bases were employed to promote cyclization of 1,5-diketone derived from D-glucose to give cyclohexanones stereoselectively. / Intramolecular nitrile oxide-alkene cycloaddition (INOC) was studied with sugar derivatives having free hydroxyl groups. The INOC reaction, by incorporating chloramine-T and silica gel for the formation of nitrile oxide from oxime, proceeded smoothly with one, two, and four unmasked hydroxyl groups to give cyclopentanes and cyclohexanes. / The polyhydroxylated carbocycles constructed from sugars were successfully transformed into a variety of target molecules including pseudo-acarviosin, valiolamine and its containing compounds and gabosines. A series of 2-crotonyloxymethyl-(4 R,5R,6R)-4,5,6-trihydroxy-2-cyclohexenone (COTC) analogues as inhibitors of hGST were prepared in order to study the structure-activity relationships. / Cheng, Hau Man. / Adviser: Tony K. M. Shing. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3508. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 214-224). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.